It is just four kilometers as the crow flies. But if you want to go from Bonn's Schießbergweg via the Rhine to the university clinic on Venusberg by public transport, you need just under an hour. It takes half as long in the car or by bike. But you are usually stuck in a traffic jam with a car, and cyclists have to overcome 120 vertical meters on the steep mountain road. The trip in a cable car gondola would be faster and more comfortable, including a panoramic view of the river and the city.

A cable car route should hardly be longer than the straight line. And where it should go best is shown in a feasibility study that has existed for three years. Other cities from Munich to Berlin to Stuttgart are considering their Ö

So far, there are cable cars in Germany only for tourism, especially in the mountains. It was not until the beginning of 2020 that they were declared an eligible part of public transport by law. However, a federal state can only co-finance them if cable cars perform well in a direct comparison with buses, trams, subways and suburban trains. However, the concrete criteria for such a balance are still missing.

Other regions of the world are further there. The largest urban cable car network covers Bolivia's seat of government, La Paz. In ten lines with a total length of 30 kilometers, 50,000 people can float up and down the steep slopes of the Andean metropolis every hour. Other South American cities and the Turkish capital, Ankara, are fighting the constant traffic jams on their streets with cable cars. French Brest is a pioneer in the EU. Since 2015, a cable car has connected two parts of the city across the military port. Over half a million passengers were counted in the first year of operation.

Nobody likes to be seen from above in the garden and on the balcony

"Cable cars are the fastest way to improve public transport," says Heiner Monheim. The traffic scientist has been dealing with the subject for three decades. Because no rails have to be laid, the construction time is considerably shorter than with trams, S-Bahn or U-Bahn. It was only four months in Brest. With the same capacity, cable cars are significantly cheaper to build and operate than buses or trains. Nobody has to wait at the stops; the next gondola will arrive after 30 seconds at the latest. The ride is also quiet and uses little energy. And because cable cars are not involved in traffic accidents, they are the safest means of transport, even if some people might get dizzy.

"But cable cars are not all-rounders," warns Monheim, "their many advantages are offset by disadvantages." This includes speed. On routes longer than seven kilometers, the bus or train are in most cases faster than gondolas. Because, for safety reasons, they only travel a maximum of 25 kilometers an hour on straight routes. Your final stops also require a relatively large amount of space and fewer stops are possible. "The routing is particularly prone to conflict," says Monheim. When the cable car is supposed to hover over traffic areas or commercial areas, this is usually not a problem. As soon as private properties have to be spanned, resistance threatens.